1. Field of the Invention.
This invention relates generally to a material handling system and more particularly to a mobile platform for the transportation of goods and personnel on the trusses which serve as work areas on a space station.
2. Description of Related Art.
The most closely related device has been studied by Langley Research Center of the National Aeronautics and Space Administration (NASA). This device walks on nodes and employs stationary tracks on the mobile platform itself. It utilizes a push-pull device to provide movement. See NASA TP 2108, entitled "A Mobile Work Station Concept for Mechanically Aided Astronaut Assembly of Large Space Trusses", dated March 1983 and JSC-19989, entitled "Space Station Reference Configuration Description", dated August 1984, pages 622-636. The disadvantage of this device is that since it uses a push-pull system for mobility, it is apparent that the traversing velocity will be non-uniform and can be changing abruptly at the start and end at each stroke. If the system is carrying large massive items such as modules, dynamic loading in the arms of the remote manipulator system can be very significant.
Other related devices comprise the following patents:
Gibbs--U.S. Pat. No. 4,372,219--a cart having orthogonally disposed wheels and means to maneuver in two directions upon a two-dimensional grid of rails;
Groger--U.S. Pat. No. 4,217,070--system for placing items, such as motor vehicles in garages, having shiftable carrying plates and occupying a plurality of respective carrying plate positions arranged throughout the available area in rows, which are transverse to each other and at right angles to each other.
Williams--U.S. Pat. No. 3,879,799--multidirectional suspension system for operable partitions having an overhead track defining a pair of vertically spaced roller-way defining ledges disposed on either side of the track, and carriers for suspending the partition panels from the track, with each carrier being in the form of a pendant bolt operating between the track ledges and having coaxially journaled thereon for rotation thereabout a pair of discs each defining a downwardly facing load support side surface, and with the load support side surfaces of one of the discs riding on one of the ledges free of contact of the other ledge, and the other of the ledges free of contact of the first ledge.
P. Rogers et al.--U.S. Pat. No. 3,845,718, a car for a tracked transporter system, supported upon wheels each of which is mounted so that it can swivel about an upright axis and one or more of which are drivable by a poser unit carried upon the car, the car being further provided with automatically actuated steering means in the track of the system and operative for imparting swiveling movement to the said wheels to cause the car selectively to follow predetermined routes or courses in the said system.
Sullivan et al.--U.S. Pat. No. 3,709,381--an article transporting system made up of a large number of individual modules, each of which is a complete and independent conveyor within itself.
Richins--U.S. Pat. No. 3,672,307--a load handling vehicle equipped with a steering and traction wheel and an overhead guide assembly co-acting with fixed overhead linear tracks.
Fonden--U.S. Pat. No. 3,356,040--a driving means for use in conveyor systems in which a rotating shaft is employed for the driving of trucks that move on tracks.
C. Rogers et al.--U.S. Pat. No. 3,273,727--an apparatus for the horizontal handling of a load, adaptable for remote control, having a floor, a pallet for use in conjunction with said floor, means for providing a fluid film between said pallet and said floor, and means for propelling said pallet over said floor.
Stein--U.S. Pat. No. 3,253,552--a system having a horizontal ceiling track in a movable wall, including parallel, spaced apart planar support members, a wall panel, and a trolley system which supports said wall panel or a movable load and which cooperates with overhead tracks.
Hellner--U.S. Pat. No. 3,094,941--track system consisting of parallel spaced rails having support surfaces extending substantially parallel with the plane of said track system, adapted to support a movable carriage thereon.
Bel Geddes--U.S. Pat. No. 2,943,579--a stage light suspended from and moveable with respect to a two-dimensional ceiling grid, such that the suspension uses two pairs of ball bearing rollers which are held by slotting rails.
Ferris--U.S. Pat. No. 460,959--a hay-carrier track having a slotted rail which engages a supporting pin.
The systems described in patents such as Hellner, P. Rogers et al., Bel Geddes, Stein, Williams, and Richins require the placement of rails or tracks along or above the desired path of travel, thus reducing the useful surface area of the object upon which the rails are placed. However, the Mobile Remote Manipulator System (referred hereafter as the "MRMS") of the present invention requires no rail placement on or above the surface of travel, but instead travels along a grid of guide pins which are located at the intersections of the elements forming the truss. These guide pins allow for transit about a work plane while freeing the overwhelming majority of the surface area and exterior for other uses.
Additionally, the MRMS of the present invention avoids the two-dimensional movement limitations of Hellner, Stein and Williams, which allow only horizontal motion, and have no self-propulsion Unlike P. Rogers et al., C. Rogers et al., Sullivan et al., Groger, Stein, Williams, Richins and probably Hellner, the MRMS of the present invention may propel itself at near-uniform velocity, in longitudinal or transverse directions and in three-dimensional space onto planes at a plurality of angles relative to one another. Unlike Williams, the MRMS of the present invention may remain in place on the surface of a truss, for instance, irrespective of gravity.
Unlike Richins, the MRMS of the present invention requires contact with only one planar surface at one time. P. Rogers et al., C. Rogers et al., Sullivan et al., Groger and perhaps Hellner teach systems which allow a moving platform or other object to move in two orthogonal directions, while implicitly depending upon the force of gravity to secure the platform to the surface. However, the MRMS of the present invention employs guide pins which allow a platform to remain secured to the surface while being transported in either longitudinal or lateral directions and onto planes at a plurality of angles relative to one another, in three-dimensional space.
Additionally, Fonden, C. Rogers et al., Sullivan et al., Groger and perhaps Hellner require equipment to enable both the translation and direction changing of the platform. However, because all the propulsion and direction changing equipment is located within the platform system element in the MRMS of the present invention, there is no need to occupy the surface upon which the platform travels with equipment other than guide pins.